1. Field of the Invention
The present invention relates to a three-dimensional laser coordinate transformation system for a three-dimensional laser machining apparatus, and more specifically, to a three-dimensional laser coordinate transformation system by which a space movement transformation or space mirror transformation can be made.
2. Description of the Related Art
A three-dimensional laser machining apparatus is employed for machining a three-dimensional model or the like because such an apparatus can machine a workpiece three-dimensionally with a high accuracy and at a high speed, without coming into contact therewith.
The three-dimensional laser machining apparatus is controlled by five axes, i.e., X-, Y- and Z-axes, and further, .alpha.- and .beta.-axes, for determining the attitude of a nozzle. More specifically, the X-, Y- and Z-axes determine a position of the extreme end of the nozzle, which is positioned perpendicular to the surface of a workpiece by the .alpha.- and .beta.-axes.
An example of such a control of the attitude of the nozzle is disclosed in Japanese Patent Application (Laid-Open) No. Hei 2-112891.
Further, in many cases, a machining program for the three-dimensional laser machining apparatus is provided with a coordinate system for each workpiece; this being determined from a particular point of the workpiece for carrying out a machining thereof. Therefore, the coordinate system employed by the machining program is different from a coordinate system of an actually set workpiece, and thus a coordinate transformation is necessary.
This coordinate transformation includes a space movement transformation by which a coordinate system having a three-dimensionally different distance and attitude is created, and a space mirror transformation by which a coordinate system symmetrical with respect to a particular plane is created.
Nevertheless, a numerical control apparatus (CNC) for controlling a three-dimensional laser machining apparatus cannot perform mirror transformations with respect to an arbitrary plane, although able to perform a mirror machining with respect to a particular plane (XY plane, YZ plane, XZ plane).
Furthermore, the numerical control apparatus does not have a function for performing a space movement transformation, and accordingly, a machining program must be created for each workpiece by an automatic program creation apparatus, after the position of the workpiece in machining has been measured, to thereby perform a space movement transformation or space mirror transformation.
Therefore, a problem arises in the use of the three-dimensional laser machining apparatus when a workpiece is to be machined in that the automatic program creation apparatus is needed at all times, and that a machining program must be created each time a workpiece is to be machined.